Pain catastrophizing is linked to a range of negative health and treatment outcomes, although debate continues about how best to define and treat it, since most interventions produce only modest benefit. This study aimed to contribute to theory-driven development of these treatments by exploring the role of perseverative thinking in pain catastrophizing, along with the higher order beliefs, called metacognitions, that might shape it.An internet sample of 510 people with chronic pain (≥3 months), who mostly (54.9%) had clinical levels of catastrophizing, completed self-report measures of pain intensity, disability, perseverative thinking, pain catastrophizing, depression, anxiety, and pain metacognition. Regression-based moderated mediation analysis tested the conditional indirect effect of pain intensity on pain catastrophizing via perseverative thinking at varying levels of unhelpful pain metacognition.Perseverative thinking partially mediated the effect of pain intensity on pain catastrophizing, accounting for 20% of the total effect. This indirect effect was conditional on both positive and negative metacognition. Higher levels of both forms of unhelpful metacognition strengthened the indirect effect, which was not significant below the 50 percentile for positive metacognitions or below the 60 percentile for negative metacognitions.Strongly believing that thinking about pain helps you solve problems or cope with pain (positive metacognition), or that it is harmful and uncontrollable (negative metacognition), can increase the amount you worry or ruminate as pain increases. This is associated with increased pain catastrophizing. Identifying and modifying these unhelpful pain metacognitions may improve treatments for pain catastrophizing and thereby chronic pain generally.